For most people when you think about fibre, you think about constipation. Yes, fibre can help prevent constipation when included in the diet, but it has many more health benefits. It was found that if only 50% of the American adult population increased their dietary intake of fibre by as little as 3g/day that it would save upwards of $2million in annual medical costs, and that’s just for constipation related medical costs (Schmier et al., 2014)!
Dietary fibre includes non-starch polysaccharides, cellulose, hemicellulose, pectin and hydrocolloids (EFSA, 2017). It is recommended that a minimum of 25g of fibre per day should be consumed (EFSA, 2017). There are three types of dietary fibre;
Soluble fibre is found in fruit, vegetables, oats, barley and legumes. It slows the emptying of the stomach so you stay fuller for longer, this may assist it weight loss. It also lowers LDL cholesterol (Nutrition Australia Victorian Division, 2014).
Insoluble fibre absorbs water in the colon, this helps prevent constipation. Insoluble fibre can be found in Wholegrain bread and cereals, seed, nuts, wheat bran and fruit & vegetable skins. It is important to drink enough water when increasing your intake of insoluble fibre as it could actually cause constipation and intestinal discomfort (Nutrition Australia Victorian Division, 2014).
Resistant starch has many health benefits (Gunnars, 2018). Studies have shown it improves insulin sensitivity (Johnston et al., 2010). It helps to lower blood sugar levels after meals (Maziarz et al., 2017). It can help aid weight loss as it gives a feeling of fullness (Bodinham et al., 2010), and it provides ½ the calories of normal starch at 2Kcals per gram (Gunnars, 2018). One of the main benefits Resistant starch provides is that is acts as a food source for friendly gut flora in the colon (Englyst et al., 1996). Most foods only feed 10% of gut flora, whereas fermentable fibres and resistant starches feed 90% (Macfarlane et al., 2006; Brown et al., 1997). Resistant starch has many health benefits with regards to colon health. It reduces the pH of the colon, decreases inflammation and greatly decreases the risk of developing colon cancer, which is the 4th most common cause of cancer deaths in the world (Hylla et al., 1998; Zimmerman et al., 2012). Resistant starch can be found in undercooked pasta, under ripe bananas, cooked and cooled potatoes and rice (Nutrition Australia Victorian Division, 2014).
Places such as rural Africa have less than ten times the rates of colon cancer than Western countries (O’Keefe et al., 2015). This has been shown not to be genetic as studies were done on migrant communities who moved from places with low rates of colon cancer, and after only one generation they assume colon cancer incidences of the host western population. The main reason for this is thought to be change in diet, as well as environmental elements such as smoking and chemicals (O’Keefe et al., 2015). When the colons of rural Africans were compared to those of African Americans and Caucasians, the Africans colons were in much better shape (O’Keefe et al., 2007). A two-week food exchange was carried out on a group of rural Africans and a group of African Americans. The African Americans ate a native African diet rich in fibre and low in animal fats, whereas the Rural Africans ate a more western diet high in animal fat and low in fibre. There were significant changes in gut health and the presence of good gut bacteria in both groups, with the African Americans gut health improving immensely and the Rural Africans gut health declining (O’Keefe et al., 2015). So this study showed that higher rates of colon cancer can be directly associated with a diet high in animal fats (saturated fats) and proteins, and low in dietary fibre (O’Keefe et al., 2015).
Another health benefit of a fibre is that it can decrease your risk of developing cardiovascular disease (Schmier et al., 2014). For every 7g of fibre eaten (that’s ½ an Avacado, 1 cup of bran flakes, 1 serving of wholegrain pasta), will reduce your risk of developing cardiovascular disease by 9% (Grooms et al., 2013)!
Other health benefits of fibre are;
fibre reduces LDL (bad) cholesterol,
it maintains blood sugar control by slowing the release of sugar into the bloodstream,
Keeps you fuller for longer, this will help with weight management
Reduces the risk of developing type 2 diabetes
All in all, I think we should all try to increase our fibre intake, but you should take things slow, especially if your diet at present is low in fibre. You aim is to get to eating 25g per day, but if you manage to get to 10-15g per day as a start that’s great! It’s all about making those little changes. Making wholegrain pasta instead of white pasta, snacking on some fresh fruit or even making up a smoothie, making your own soups, sauces, curries and casseroles and adding in as much veg and beans and lentils as you can to pack those yummy dishes full of goodness.
References
Bodinham, C.L., Frost, G.S. and Robertson, M.D. (2010) Acute ingestion of resistant starch reduces food intake in healthy adults. The British Journal of Nutrition, 103(6) 917–922.
Brown, I., Warhurst, M., Arcot, J., Playne, M., Illman, R.J. and Topping, D.L. (1997) Fecal numbers of bifidobacteria are higher in pigs fed Bifidobacterium longum with a high amylose cornstarch than with a low amylose cornstarch. The Journal of Nutrition, 127(9) 1822–1827.
EFSA (2017) Dietary Reference Values for nutrients Summary report. 92. Available from https://www.efsa.europa.eu/sites/default/files/2017_09_DRVs_summary_report.pdf.
Englyst, H.N., Kingman, S.M., Hudson, G.J. and Cummings, J.H. (1996) Measurement of resistant starch in vitro and in vivo. The British Journal of Nutrition, 75(5) 749–755.
Grooms, K.N., Ommerborn, M.J., Pham, D.Q., Djoussé, L. and Clark, C.R. (2013) Dietary Fiber Intake and Cardiometabolic Risks among US Adults, NHANES 1999-2010. The American Journal of Medicine, 126(12) 1059-1067.e4. Available from http://www.sciencedirect.com/science/article/pii/S0002934313006311 [accessed 10 November 2020].
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Hylla, S., Gostner, A., Dusel, G., Anger, H., Bartram, H.P., Christl, S.U., Kasper, H. and Scheppach, W. (1998) Effects of resistant starch on the colon in healthy volunteers: possible implications for cancer prevention. The American Journal of Clinical Nutrition, 67(1) 136–142.
Johnston, K.L., Thomas, E.L., Bell, J.D., Frost, G.S. and Robertson, M.D. (2010) Resistant starch improves insulin sensitivity in metabolic syndrome. Diabetic Medicine, 27(4) 391–397. Available from https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1464-5491.2010.02923.x [accessed 21 November 2019].
Macfarlane, S., Macfarlane, G.T. and Cummings, J.H. (2006) Review article: prebiotics in the gastrointestinal tract. Alimentary Pharmacology & Therapeutics, 24(5) 701–714.
Maziarz, M.P., Preisendanz, S., Juma, S., Imrhan, V., Prasad, C. and Vijayagopal, P. (2017) Resistant starch lowers postprandial glucose and leptin in overweight adults consuming a moderate-to-high-fat diet: a randomized-controlled trial. Nutrition Journal, 16. Available from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5320660/ [accessed 21 November 2019].
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Schmier, J.K., Miller, P.E., Levine, J.A., Perez, V., Maki, K.C., Rains, T.M., Devareddy, L., Sanders, L.M. and Alexander, D.D. (2014) Cost savings of reduced constipation rates attributed to increased dietary fiber intakes: a decision-analytic model. BMC public health, 14 374.
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